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Network planning and design is an iterative process, encompassing topological design, network-synthesis, and network-realization, and is aimed at ensuring that a new telecommunications network or service meets the needs of the subscriber and operator. The process can be tailored according to each new network or service.
1 | A Network Planning Methodology
2 | The Role of Forecasting
3 | Dimensioning
4 | Traffic Engineering
5 | Survivability
6 | Tools
1 | A Network Planning Methodology
A traditional network planning methodology in the context of business decisions involves five layers of planning, namely:
- Need Assessment and Resource Assessment
- Short-term Network Planning
- IT Resource
- Long-term and Medium-term Network Planning
- Operations and Maintenance.
Each of these layers incorporates plans for different time horizons, i.e. the business planning layer determines the planning that the operator must perform to ensure that the network will perform as required for its intended life-span. The Operations and Maintenance layer, however, examines how the network will run on a day-to-day basis.
The network planning process begins with the acquisition of external information. This includes:
- Forecasts of how the new network/service will operate;
- The economic information concerning costs; and
- The technical details of the network’s capabilities.
Planning a new network/service involves implementing the new system across the first four layers of the OSI Reference Model. Choices must be made for the protocols and transmission technologies.
Network planning process involves three main steps:
- Topological Design: This stage involves determining where to place the components and how to connect them. The (topological) optimisation methods that can be used in this stage come from an area of mathematics called Graph Theory. These methods involve determining the costs of transmission and the cost of switching, and thereby determining the optimum connection matrix and location of switches and concentrators.
- Network-Synthesis: This stage involves determining the size of the components used, subject to performance criteria such as the Grade of Service (GOS). The method used is known as “Nonlinear Optimisation”, and involves determining the topology, required GoS, cost of transmission, etc., and using this information to calculate a routing plan, and the size of the components.
- Network Realization: This stage involves determining how to meet capacity requirements, and ensure reliability within the network. The method used is known as “Multicommodity Flow Optimisation”, and involves determining all information relating to demand, costs and reliability, and then using this information to calculate an actual physical circuit plan.
These steps are performed iteratively in parallel with one another.
2 | The Role of Forecasting
During the process of Network Planning and Design, estimates are made of the expected traffic intensity and traffic load that the network must support. If a network of a similar nature already exists, traffic measurements of such a network can be used to calculate the exact traffic load. If there are no similar networks, then the network planner must use telecommunications forecasting methods to estimate the expected traffic intensity.
The forecasting process involves several steps:
- Definition of problem;
- Data acquisition;
- Choice of forecasting method;
- Documentation and analysis of results.
3 | Dimensioning
Dimensioning a new network determines the minimum capacity requirements that will still allow the Teletraffic Grade of Service (GoS) requirements to be met. To do this, dimensioning involves planning for peak-hour traffic, i.e. that hour during the day during which traffic intensity is at its peak.
The dimensioning process involves determining the network’s topology, routing plan, traffic matrix, and GoS requirements, and using this information to determine the maximum call handling capacity of the switches, and the maximum number of channels required between the switches. This process requires a complex model that simulates the behavior of the network equipment and routing protocols.
A dimensioning rule is that the planner must ensure that the traffic load should never approach a load of 100 percent. To calculate the correct dimensioning to comply with the above rule, the planner must take on-going measurements of the network’s traffic, and continuously maintain and upgrade resources to meet the changing requirements. Another reason for overprovisioning is to make sure that traffic can be rerouted in case a failure occurs in the network.
Because of the complexity of network dimensioning, this is typically done using specialized software tools. Whereas researchers typically develop custom software to study a particular problem, network operators typically make use of commercial network planning software.
4 | Traffic Engineering
Compared to network engineering, which adds resources such as links, routers and switches into the network, traffic engineering targets changing traffic paths on the existing network to alleviate traffic congestion or accommodate more traffic demand.
This technology is critical when the cost of network expansion is prohibitively high and network load is not optimally balanced. The first part provides financial motivation for traffic engineering while the second part grants the possibility of deploying this technology.
5 | Survivability
Network survivability enables the network to maintain maximum network connectivity and quality of service under failure conditions. It has been one of the critical requirements in network planning and design. It involves design requirements on topology, protocol, bandwidth allocation, etc.. Topology requirement can be maintaining a minimum two-connected network against any failure of a single link or node. Protocol requirements include using dynamic routing protocol to reroute traffic against network dynamics during the transition of network dimensioning or equipment failures. Bandwidth allocation requirements pro-actively allocate extra bandwidth to avoid traffic loss under failure conditions. This topic has been actively studied in conferences, such as the International Workshop on Design of Reliable Communication Networks.
6 | Tools
There are a wide variety of tools available for network planning and design depending on the technologies being used. These include:
OPNET Technologies, Inc. was a software business that provided performance management for computer networks and applications.
The company was founded in 1986 and went public in 2000. In October 2012, OPNET was acquired by Riverbed Technology, for about $1 billion US dollars.
Prior to Riverbed, OPNET was headquartered in Bethesda, Maryland and had U.S. offices in Cary, North Carolina; Nashua, New Hampshire; Dallas, Texas; and Santa Clara, California. It had international offices in Slough, United Kingdom; Paris, France; Ghent, Belgium; Frankfurt, Germany; and Singapore, with staff and consultants in multiple locations in Asia and Latin America.
“OPNET” was Alain Cohen’s (co-founder, CTO & President) graduate project for a networking course while he was at MIT. OPNET stood for Optimized Network Engineering Tools. Alain, along with brother Marc (co-founder, CEO & Chairman) and classmate Steven Baraniuk, decided to commercialize the software. The company’s first product was OPNET Modeler, a software tool for computer network modeling and simulation.
Since becoming a public company in August 2000, OPNET executed the following acquisitions:
- March 2001: NetMaker Division of Make Systems
- January 2002: WDM NetDesign B.V.B.A
- October 2004: Altaworks Corporation
- October 2007: substantially all of the assets of Network Physics, Inc.
- August 2010: DSAuditor product line from Embarcadero Technologies
- May 2012: Clarus Systems, Inc.
As an independent company, OPNET grew profitably throughout its history. SEC filings are available with further information about its IPO, annual reports, and quarterly reports.
OPNET Solutions (prior to acquisition by Riverbed)
- Application performance management, see AppTransaction Xpert in Comparison of packet analyzers
- Network performance management
NetSim is a network simulation and network emulation tool used for network design & planning, defense applications and network R & D. Various technologies such as Cognitive Radio, Wireless Sensor Networks, Wireless LAN, Wi Max, MANETs, Wireless Sensor Networks, LTE, etc. are covered in NetSim.
NetSim is a stochastic discrete event simulator developed by Tetcos, in association with Indian Institute of Science, with the first release in June 2004.
Model Libraries in NetSim
- Modeling and simulation are supported for the below mentioned technologies. Protocol libraries are available with C source code
- Inter-Networks:Ethernet – Fast & Gigabit, ARP, WLAN – IEEE 802.11 a/ b / g / n / ac and e. Propagation models – Free space, Log-normal, Rayleigh Fading. Routing – RIP, OSPF. Queuing – Round Robin, FIFO, Priority TCP – Tahoe, Reno, New Reno, BIC and CUBIC, UDP
- Common Modules with Internetworks: Applications (Traffic Generator): Voice, Video, FTP, Database, HTTP, Email, Peer-to-peer and Custom. Encryption: AES, DES. Virtual Network Stack, Simulation Kernel, Command Line Interface, Wireshark Interface, Metrics Engine with Packet Trace and Event Trace, Packet Animator
- Legacy Networks – Aloha, Slotted Aloha, Token Ring, Token Bus, CSMA/CD
Advanced Wireless Networks – Wi-Max, MANET covering DSR, AODV, ZRP, OLSR etc. with sinkhole / black hole attacks and intrusion detection
- Cellular Networks – GSM and CDMA
- Sensor Networks – Wireless Sensor Network with LEACH etc., Zigbee
- Internet of Things (IOT) with Routing Protocol for Low Power and Loss Networks (RPL)
- Cognitive radio Networks
- LTE Networks, LTE Advanced Networks – SU / MU MIMO with Carrier aggregation and Relays, LTE D2D, LTE Femto Cell
- VANETs with interfacing to SUMO through TraCI API’s
- Military Radios – Tactical and Airborne radios in HF, VHF, UHF bands with crypto and frequency hopping,. Tactical data links, TDMA Link 16, Dynamic TDMA
In addition modules are available for sink hole attack, intrusion detection, packet encryption, packet capture using Wireshark etc.
The Network Emulator Add on allows users to link NetSim to live applications running on real devices. This allows for real traffic to flow via the emulator and experience network effects. In this virtual network, numerous test scenarios, involving real devices and application, can be constructed and executed repetitively for normal operation as well as perturbed operation. Impairment scenarios can studied which included escalating latency, bandwidth constriction at various points, jitter tolerance, packet loss, packet reordering, route loss, failovers and single point of failure identification.
NetSim can interface externally with MATLAB, Wireshark, LabVIEW and SUMO for VANETs. NetSim can also interface with live PC’s / Sensors using the emulation add-on module.
A deeply discounted academic version is available to universities for teaching and conducting network lab practicals. No student version is available as of date.
NetSim is widely used for
- Network R & D including custom protocol development
- Network lab experimentation in universities
- Defense applications
- Railway communication networks
- Utilities transmission and distribution – SCADA Communication Networks.
- Water/Waste Water, Electric Grid and Oil & Gas
- Wireless / Satellite link emulation
Custom Code Development
NetSim comes with an in-built development environment, which serves as the interface between User’s code and NetSim’s protocol libraries and simulation kernel. Protocol libraries are available as open C code for user modification. De-bugging custom code during simulation is an advanced feature: i.e. a simulation can be started and then at user determined breakpoints in the code, users can perform single-step, step-in, step over etc. This can be carried out at various levels (depending on where the user code links) including at a per-packet interval.
Over 300 customers across 15 countries use NetSim, including premier enterprises like Philips, Hindustan Aeronautics, Indonesian Aerospace, BSNL etc. and several defense agencies like DRDO labs and space agencies like ISRO use NetSim for modeling the unique requirements of space, defense R & D and Network-centric warfare.
Hundreds of academic institutions such as Ingolstadt University – Germany, De Montfort University – UK, INTI – Malaysia, Barry University – US, Indian_Institutes_of_Technology, Dar Al Hekma – Saudi Arabia etc also use NetSim for teaching / lab experimentation and for network R & D.